Genetics final according to his list Flashcards
Cell theory, the different dates, what was found by who.
- 1665 - Robert Hooke, observed cells for the first time
- 1683 - Anton van Leeuwenhoek, discovered living organisms in water
- 1833 - Brown, discovered the nucleus in the cell
- 1858 - Rudolf Virchow, summarized the state of the current knowledge in Latin. (All cells come from preexisting cells)
Evolution theory, when? By who? What?
- In 1859
- By Charles Darwin
- Theory about the origin of species. Including work about natural selection.
Mendel laws, When? By who? What are they?
- 1865, by Gregor Mendel
- The law of segregation - Alleles segregate randomly into gametes
- The law of independent assortment - genes do not influence each other with regard to the sorting of alleles into gametes
- The law of dominance - If you breed two individuals with different traits the next generation will have one of each. The trait that is visible is the dominant one.
Chromosomal theory, Theodor Boveri, Walter Sutton and Walter Fleming, what did they discover?
- Theodor Boveri - Studied roundworms with only two pairs of chromosomes. He found that only the germline retained full chromosome complement.
- Walter Sutton - Used testes of a lubber grasshopper to trace 11 chromosome pairs and one singleton - the sex chromosome
(Chromosomal theory of inheritance) - Walter Fleming - Discovered Chromatin and described mitosis by using innovative microscopy
Chromosomal theory, what did Thomas Hunt Morgan try to prove and when?
- He tried to prove that hereditary traits are carried by chromosomes. He did this by using fruit flies.
- He tried to prove this in 1910
Transforming factor, What did Frederick Griffith discover and when?
- Frederick Griffith - discovered bacterial transformation, in 1928.
Who solved the mystery of the transforming principle and when?
- Oswald Avery
- Colin MacLeod
- Maclyn McCart
- in 1944 using a process of elimination
DNA structure was found by who and when?
- F. crick, J. Watson, R. Franklin and M. Wilkins
- 1953
- They identified the double helix structure of DNA
Genetic code, founded by who and when?
- Khorana, Nirenberg and Ochoa
- In 1966
One gene-one enzyme, order
Archibald Garrod - suggested that genes were connected to enzymes
Beadle and Tatum - confirmed the hypothesis
(each gene controls the synthesis or activity of a single enzyme.)
Transposons, restriction enzymes
Jumping genes - identified in 1948 by Barbara McClintock
General information about DNA sequencing now and then
- Fredric Sanger revealed a new method for DNA sequencing in 1977
- Now newer methods have drastically cut the cost of sequencing. This may at some point allow every person the possibility of personalized genome information.
Nuclear and mitochondrial genome
Nuclear genome:
- 3 200 000 000 base pairs in 23 linear particles - chromosomes
- 22 autosomes and 2 sex chromosomes
- totally ca. 20 000 - 25 000 genes
Mitochondrial genome:
- 16 569 base pairs in 1 circular particle
- Contains 37 genes
- Many copies in the mitochondria
Cell cycle
The cell cycle is divided into I for Interphase and M for mitosis/meiosis
Interphase consists of:
- G1 - the gap 1 phase
- S - the synthesis phase
- G2 - the gap 2 phase
- G0 - the resting phase
Mitosis - stages and events
- Prophase:
– Chromatids become linked with centrioles
– Centrioles travel to the poles
– Nucleolus disappears
– Nuclear membrane disappears - Metaphase:
– Development of the spindle apparatus
– Chromatids are still linked by centromeres
– Chromosomes are located in a line in the middle - Anaphase:
– Microtubules shrink
– Sister chromatids travel to the cell’s poles - The amount of genetic material changes
- Telophase:
– Nuclear membrane development
– Centriole division
– Nucleolus development - Cytokinesis:
– Midbody structure formation
– Cell regeneration
Meiosis - stages and events
- Prophase 1:
– A step where crossing over can occur.
– Nucleolus disappears
– Nuclear membrane disappears
Metaphase 1:
– Development of the spindle apparatus
– Chromatids are still linked by centromeres
– Chromosomes are located in a line in the middle
- Anaphase 1:
– Microtubules shrink
– Sister chromatids travel to the cell’s poles - The amount of genetic material changes
- Telophase 1 and cytokinesis:
– Nuclear membrane development
– Nucleolus development
– Cytoplasm division
Prophase 2, Metaphase 2, Anaphase 2 and Telophase 2 + Cytokinesis are pretty much the same further on.
Meiosis crossing over in detail
Its when each C-O reduces the chance of the next C-O in the close location. This is called interference and guarantees that C-O sites will be evenly spread across the chromosome and different chromosomes.
Meiosis genetic diversity and recombination
- It is the secondary source of genetic diversity through recombination
Genetic recombination:
1. non-sister chromatids exchange their parts - crossing over in prophase 1
- Chromosomes are shuffled and separated to new nuclei - anaphase 1
- Chromatids are shuffled and separated to new cells - anaphase 2
Sexual reproduction, what is the role of sexual reproduction and gametogenesis, male vs female
Gametogenesis - cell division and differentiation leading to formation of haploid gametes with recombined chromosomes
what is the role of sexual reproduction?:
- Increasing the biodiversity inside a species, that allows the population to survive in a changing environment
Male and female gametogenesis is just meiosis but the end result is sperm and oocytes
Polytene chromosomes, balbiani rings/puffs
Polytene chromosomes:
- develop from the chromosomes of diploid nuclei by successive duplication of each chromosomal element (chromatid) without their segregation
Balbiani rings/puffs:
- a large chromosome puff in the polytene chromosome
Interphase chromatin organization
- relatively decondensed and distributed throughout the nucleus
Nucleosome structure (with histone names)
Histone names:
- H2A, H2B, H3, and H4.
Chromosome structure and morphology
We also name them based on where the centromere is placed:
1. Telocentric - two equal legs are made and the centromere is just on top
- Acrocentric - similar, but it has two tiny arms on top
- Submetacentric - same again, but the arms get longer
- Metacentric - normal chromosome length (all arms equal)
Karyotype, definition, human
- The number and the appearance of chromosomes in the nucleus of an eukaryotic cell sorted by their decreasing length in homologous pairs
Human karyogram includes:
- 22 chromosome pairs + 2 sex chromosomes
G-banding, what stain and what does it show?
Giemsa stain
- It shows darker colors in regions with high A-T content
- Light color in active regions
Q-banding, what stain and what does it show?
Quinacrine stain
- It shows fluorescent bands in regions with high A-T content
R-banding, what stain and what does it show?
Reverse Giemsa stain
- It shows dark bands in places with high G-C content
(Inverted G-banding)
C-banding, what stain and what does it show?
Constitutive heterochromatin stain
- Dark bands in densely packed heterochromatic regions
